Energetic demands of interchange and full-match rugby league players

Cloe Cummins, Adrian Gray, Kathleen Shorter, Mark Halaki, Rhonda Orr

Journal of Strength and Conditioning Research 2017 January 20

28135224

The purpose of this study was to describe and compare the metabolic demands of rugby league for interchange and full-match players in relation to positional groups. Eighteen elite rugby league players were recruited. A time-motion model was used to estimate the energy expenditure and metabolic demands of rugby league match-play utilizing Global Positioning System (GPS) technology. This approach utilizes players' GPS velocity-time curves to examine running velocity. Players were categorized into positional groups (outside backs, adjustables, wide-running and hit-up forwards) and then further categorized into full-match or interchange players. Compared to their full-match counterparts, interchange wide-running forwards expended greater energy (43.1±6.1 vs 28.6±7.5 kJ·kg, p≤ 0.001, ES=-2.38) and produced a higher anaerobic index (p=0.016, ES=0.56) and mean power (7.4%, p=0.003, ES=0.66) per match. Full-match adjustables expended 94.8% more energy (p≤ 0.001, ES=-2.3) and performed more moderate accelerations (10.1%, p=0.014, ES=-0.57) and decelerations (7.6%, p=0.017, ES=-0.8), than their interchange counterparts. Outside backs did not interchange and hit-up forwards rarely (n=2) played an entire match. Differing metabolic demands were identified for interchange and full-match players across positional groups, suggesting position specific conditioning drills are required to model the energetic demands of match-play.